When someone wrote something down 500 years ago, just the act of writing means they were educated and there is some value in their perspective. In the age we live in, there is information overload for a historian to pick through. How will historians know how to sift through all of the noise?
What is "meaningful" depends on the historical question you are trying to answer. We cannot predict what questions historians of the future will be asking. Don't worry. They'll figure it out. Or at least have a fun time arguing about it.
I think part of the reason this isn't getting a lot of response is that the question has some faulty assumptions. That being said, I think the assumptions are pretty widely held, so I'll take the opportunity to address three of them and hopefully answer your question along the way.
First, there are a lot of historians (and other social sciences/humanists, etc.) who are working on dealing with huge data sets in their work. Without getting into too much of the methodology here, the data set itself becomes the "source" that is analyzed. This is one way to deal with the huge amount of information without "picking through" as you describe.
But that's only part of your question.
So, second, the other part assumes that education of the writer is a primary consideration when analyzing a source. It is certainly a variable worth knowing and understanding, but not because the more educated you are the more likely you are to have "value" to your perspective. EVERY source has a perspective and it is the historian's job to try to understand that perspective in order to critically analyze the source. As /u/restricteddata suggests historians of the future may very well be interested in questions that are best answered by information left behind by uneducated people. Indeed, everyday life is already a common topic in historical studies and everyday life is lived by, well, everyone.
And that gets to the third and final point. Historians don't rely on sources to accurately recount the past to us and thereby pass along a narrative that we can use in our work. We construct those narratives through all kinds of evidence and the education level of the person who wrote or created a particular piece of evidence is not at all reason that we should take it to be a "better" source (leaving aside just how muddy that particular evaluation of sources would be to begin with).
So, to make a long story short, historians of the future will be evaluating all kinds of evidence we've left behind and they'll be doing so while asking questions that make sense to ask 500 years hence. Maybe a giant database of tweets from 2019 will be of use to them, or maybe not. But they certainly shouldn't, and almost certainly won't, look at our degrees and think "Ok, these people are the only ones we need to take seriously"